§ 680-d. Requirements for special deposit. A deposit is a special deposit if it is: 1. a deposit of funds in a bank under an account agreement; 2. for the benefit of at least two beneficiaries, one or more of which may be a depositor; 3. denominated in a medium of exchange that is currently authorized or adopted by a domestic or foreign government; 4. for a permissible purpose stated in the account agreement; and 5. subject to a contingency.